In conventional rotating disk files, the read/write transducers (or heads) are supported on sliders which ride on cushions or bearings of air above the disk surface when the disks are rotating at operating speed. The slider is connected to a linear or rotary voice coil actuator by means of a relatively fragile suspension. In large capacity magnetic recording disk files, there is generally a stack of rigid disks and a number of actuators with each actuator supporting a number of sliders. The actuators move the sliders generally radially between the disks so that each head may access the recording area of a respective disk. In these conventional disk files, the slider is biased against the disk surface by a small force from the suspension when the disk is not rotating. The slider is thus in contact with the disk surface from the time the disk file is turned on until the disk reaches a speed sufficient to cause the slider to ride on the air bearing. The slider is again in contact with the disk surface when the disk file is turned off and the rotational speed of the disk falls below that necessary to create the air bearing.
One type of magnetic recording disk used in disk files is a thin film metal alloy or metal oxide disk which has a protective overcoat of essentially carbon. The carbon overcoat protects the magnetic layer of the disk from corrosion as well as wear caused by contact by the air bearing surface of the slider supporting the read/write head. A liquid lubricant such as a perfluoroether, is typically applied to the carbon overcoat.
Protective carbon overcoats for thin film metal alloy disks are well known. They are typically formed by sputter deposition from a graphite target, and are generally referred to merely as protective carbon overcoats, sputtered carbon overcoats, "diamondlike" carbon overcoats, amorphous carbon overcoats, or, in the case of those overcoats formed by sputter deposition in the presence of a hydrogen containing gas, hydrogenated carbon overcoats. Tsai, et al in "Structure and Properties of Sputtered Carbon Overcoats on Rigid Magnetic Media Disks," J. Vac Science Technology A6(4), July/August 1988, pp. 2307-2314, describe such protective carbon overcoats and refer to them as amorphous "diamondlike" carbon films, the "diamondlike" referring to their hardness rather than their crystalline structure. Assignee' U.S. Pat. No. 4,778,582, issued Oct. 18, 1988, describes the prior art of thin film disk amorphous hydrogenated carbon overcoats and a sputter deposition process for forming such an overcoat.
Recent advances in read/write head technology have resulted in the possible use of magnetoresistive (MR) read heads in disk files. Unlike conventional inductive heads, MR heads, due to the material from which they are fabricated, are highly susceptible to corrosion. Accordingly, in order to assure proper operation of such heads in disk files, including those which use carbon overcoated disks, it is necessary to operate the disk file at very low humidity. However, it has been discovered that when disk files with carbon overcoated disks are operated at low humidity in conjunction with TiC/Al.sub.2 O.sub.3 sliders, the disks wear at an extremely high rate.